The need for power conservation is known. All else being equal and assuming an upper bound on energy density for battery technology, there is a direct tradeoff between portable product package weight and the length of time the product may be used without recharging or replacing an associated battery. Removing the equality qualifier, practitioners continually struggle with tradeoffs and compromises among product utility, product processing speed, memory, capability, product size, product weight, useful battery life, and battery technology with its attendant limitations. Almost all agree that compromise is the operative word, no really satisfactory answer having yet been found, and additional power conservation approaches are needed.
A particularly appropriate case in point is that of battery powered data terminals, and more specifically their associated data modems. Wireless data communications systems, protocols, network or infrastructure equipment, and modems together with their host terminals have evolved to provide communications service to a growing user base on both outbound and inbound channels. This data communications service is highly dependent on the specific user and that user's needs, but may be characterized as sporadic and highly interactive with varying message lengths, content, and protocols. As a result of these characteristics equipment suppliers necessarily have emphasized processing speed, accuracy, and user interaction often at the expense of power consumption. More recently the data communications marketplace has begun, and is expected to continue, to demand portable data terminals (and thus data modems) that are the functional equivalent of a portable computer combined with a portable two way radio. This market requirement has focused attention on product size and weight (and on battery life) and power conservation, since they affect size and weight.
In contrast, personal paging systems, protocols, and equipment have evolved to service a large user base on outbound channels only, on a non-real-time critical basis, where message lengths and content are limited. Premiums are placed on low system cost message delivery and subscriber unit battery life. Various techniques for conserving power (and hence extending battery life) in a paging environment have been employed. However, all such techniques are sub optimal or can be significantly improved upon once the basic limitation of paging systems, specifically a one-way or outbound-only channel, is eliminated.
Clearly a need exists for inventive approaches to conserving power (and thus extending the battery life) of portable communications equipment and more specifically data communications modems.